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/**
* Copyright (c) 2018 Metempsy Technology Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Javier Bueno
*/
#ifndef __CACHE_PREFETCH_ASSOCIATIVE_SET_HH__
#define __CACHE_PREFETCH_ASSOCIATIVE_SET_HH__
#include "mem/cache/replacement_policies/base.hh"
#include "mem/cache/replacement_policies/replaceable_entry.hh"
#include "mem/cache/tags/indexing_policies/base.hh"
/**
* Entry used for set-associative tables, usable with replacement policies
*/
class TaggedEntry : public ReplaceableEntry {
/** Tag for the entry */
Addr tag;
/** Valid bit */
bool valid;
/** Whether this entry refers to a memory area in the secure space */
bool secure;
public:
TaggedEntry() : tag(0), valid(false), secure(false) {}
virtual ~TaggedEntry() {}
/**
* Consult the valid bit
* @return True if the entry is valid
*/
bool isValid() const
{
return valid;
}
/**
* Sets the entry to valid
*/
void setValid()
{
valid = true;
}
/**
* Sets the entry to invalid
*/
void setInvalid() {
valid = false;
}
/**
* Obtain the entry tag
* @return the tag value
*/
Addr getTag() const
{
return tag;
}
/**
* Sets the tag of the entry
* @param t the tag value
*/
void setTag(Addr t)
{
tag = t;
}
/**
* Consult if this entry refers to a memory in the secure area
* @return True if this entry refers to secure memory area
*/
bool isSecure() const
{
return secure;
}
/**
* Sets the secure value bit
* @param s secure bit value
*/
void setSecure(bool s)
{
secure = s;
}
/**
* Resets the entry, this is called when an entry is evicted to allocate
* a new one. Types inheriting this class should provide its own
* implementation
*/
virtual void reset () {
}
};
/**
* Associative container based on the previosuly defined Entry type
* Each element is indexed by a key of type Addr, an additional
* bool value is used as an additional tag data of the entry.
*/
template<class Entry>
class AssociativeSet {
static_assert(std::is_base_of<TaggedEntry, Entry>::value,
"Entry must derive from TaggedEntry");
/** Associativity of the container */
const int associativity;
/**
* Total number of entries, entries are organized in sets of the provided
* associativity. The number of associative sets is obtained by dividing
* numEntries by associativity.
*/
const int numEntries;
/** Pointer to the indexing policy */
BaseIndexingPolicy* const indexingPolicy;
/** Pointer to the replacement policy */
BaseReplacementPolicy* const replacementPolicy;
/** Vector containing the entries of the container */
std::vector<Entry> entries;
public:
/**
* Public constructor
* @param assoc number of elements in each associative set
* @param num_entries total number of entries of the container, the number
* of sets can be calculated dividing this balue by the 'assoc' value
* @param idx_policy indexing policy
* @param rpl_policy replacement policy
* @param initial value of the elements of the set
*/
AssociativeSet(int assoc, int num_entries, BaseIndexingPolicy *idx_policy,
BaseReplacementPolicy *rpl_policy, Entry const &init_value =
Entry());
/**
* Find an entry within the set
* @param addr key element
* @param is_secure tag element
* @return returns a pointer to the wanted entry or nullptr if it does not
* exist.
*/
Entry* findEntry(Addr addr, bool is_secure) const;
/**
* Do an access to the entry, this is required to
* update the replacement information data.
* @param entry the accessed entry
*/
void accessEntry(Entry *entry);
/**
* Find a victim to be replaced
* @param addr key to select the possible victim
* @result entry to be victimized
*/
Entry* findVictim(Addr addr);
/**
* Find the set of entries that could be replaced given
* that we want to add a new entry with the provided key
* @param addr key to select the set of entries
* @result vector of candidates matching with the provided key
*/
std::vector<Entry *> getPossibleEntries(const Addr addr) const;
/**
* Indicate that an entry has just been inserted
* @param addr key of the container
* @param is_secure tag component of the container
* @param entry pointer to the container entry to be inserted
*/
void insertEntry(Addr addr, bool is_secure, Entry* entry);
};
#endif//__CACHE_PREFETCH_ASSOCIATIVE_SET_HH__
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